Electronic camera

ABSTRACT

An electronic camera of the present invention includes an image pickup part performing “still image pickup generating a still image signal” and “control image pickup successively generating control image signals having higher frame rate” in time division; a still image processing part applying predetermined still image signal processing to the still image signal; a control image processing part applying predetermined control signal processing to the control image signals to extract control data; and a control part performing at least one control operation out of exposure control, focus control, and white balance control, based on the control data output from the control image processing part. Particularly, in the present invention, the control image processing part and the still image processing part are configured to operate independently. The control image processing part performs the signal processing on the control image signals successively generated, even when the still image signal is being signal-processed.

FIELD OF THE INVENTION

[0001] The present invention relates to an electronic camera whichperforms still image pickup and monitor image pickup (or control imagepickup) of high frame rate in time division.

DESCRIPTION OF THE BACKGROUND ART

[0002] Conventionally, there have been known electronic cameras thatpick up monitor images at high frame rate and, in response to a releaseoperation by a photographer, perform still image pickup at highresolution.

[0003] By the way, electronic cameras of this kind typically performsignal processing on a still image (such as tone conversion, colorinterpolation, and image compression) with priority, immediately after astill image is picked up.

[0004] When still image processing is thus performed by priority, thetime before checking the monitor of the still image signal can bereduced as much as possible. In addition, image compression is startedquickly to ease the memory size of the image data, so that there is anadvantageous effect that there can be increase in the number of possibleexposures when continuously shooting.

[0005] While performing such still image processing, however, it was anecessity to stop picking up the monitor image or stop processing themonitor signal. Because of that, there have been problems of the monitordisplay being interrupted, or control operations of electronic camerasthat use monitor images (such as focus control) being interrupted.

[0006] Such interruptions have caused a time lag such that the focuscontrol of the electronic camera is exercised again, producing theadverse effect of delaying the next monitor display and still imagepickup. Recently in particular, the foregoing adverse effect has had apropensity to grow in influence because the processing time of stillimages is on the increase due to electronic cameras having higherresolutions.

DISCLOSURE OF THE INVENTION

[0007] In view of the foregoing problem, it is thus an object of thepresent invention to provide an electronic camera which performs signalprocessing on image signals of high frame rate picked up in succession,even when a still image is being signal-processed.

[0008] Hereinafter, the contents of claims of the present invention willbe described item by item.

[0009] (1) An electronic camera of the present invention comprises animage pickup part, a still image processing part, a control imageprocessing part, and a control part.

[0010] This image pickup part performs “still image pickup for shootinga subject image to generate a still image signal” and “control imagepickup for successively generating control image signals having a framerate higher than that of the still image signal” in time division.

[0011] Moreover, the still image processing part accepts the still imagesignal generated by the image pickup part and applies predeterminedstill image signal processing to this still image signal.

[0012] Furthermore, the control image processing part accepts thecontrol image signals generated by the image pickup part and appliespredetermined control signal processing to these control image signalsto extract control data.

[0013] Besides, the control part accepts the control data output fromthe control image processing part and performs at least one controloperation out of exposure control, focus control, and white balancecontrol, based on this control data.

[0014] In particular, the present invention is characterized in that thecontrol image processing part and the still image processing partmentioned above are configured to operate independently, and the controlimage processing part performs the signal processing on the controlimage signals successively generated, even when the still image signalis being signal-processed.

[0015] In such a configuration, the control image processing part canprocess the control image signals picked up in succession by the imagepickup part so that the control data is extracted smoothly even when thestill image signal is being processed.

[0016] As a result, the continuous extracting of the control data willnot be needlessly interrupted, even in the course of processing thestill image signal. Therefore, it becomes possible to obtain controldata as continuously as possible, and the adverse effect, that controloperations may be delayed because they follow discontinuous change inthe control data, can be mended.

[0017] (2) Moreover, another electronic camera of the present inventioncomprises an image pickup part, a still image processing part, and amonitor-image processing part.

[0018] This image pickup part performs “still image pickup for shootinga subject image to generate a still image signal” and “monitor-imagepickup for successively generating monitor-image signals having a framerate higher than that of the still image signal” in time division.

[0019] Besides, the still image processing part accepts the still imagesignal generated by this image pickup part and applies predeterminedstill image signal processing to this still image signal.

[0020] Furthermore, the monitor-image processing part accepts themonitor-image signals generated by the image pickup part and appliespredetermined monitor signal processing to these monitor-image signals.

[0021] In particular, the present invention is characterized in that themonitor-image processing part and the still image processing part areconfigured to operate independently, and the monitor-image processingpart performs the signal processing on the monitor-image signalssuccessively generated, even when the still image signal is beingsignal-processed.

[0022] In such a configuration, the monitor-image processing part cansmoothly process the monitor-image signals picked up in succession bythe image pickup part, even when the still image signal is beingprocessed.

[0023] As a result, monitor images are displayed without uselessly beinginterrupted even in the course of processing the still image signal. Themonitor images can thus be displayed as continuously as possible.

[0024] (3) Furthermore, another electronic camera of the presentinvention is the electronic camera as set forth in the foregoing section(2), comprising a control image processing part and a control part.

[0025] This control image processing part accepts the monitor-imagesignals generated by the image pickup part and applies predeterminedcontrol signal processing to these monitor-image signals to extractcontrol data.

[0026] Besides, the control part accepts the control data output fromthe control image processing part and performs at least one controloperation out of exposure control, focus control, and white balancecontrol, based on this control data.

[0027] In particular, the present invention is characterized in that thecontrol image processing part and the still image processing part areconfigured to operate independently, and the control image processingpart performs the signal processing on the monitor-image signalssuccessively generated, even when the still image signal is beingsignal-processed.

[0028] In such a configuration, “the extraction of the control data” and“the monitor signal processing” will not be needlessly interrupted, evenin the course of processing the still image signal. Therefore, theadverse effect that subsequent monitor displays and control operationsare delayed can be mended.

[0029] (4) Furthermore, another electronic camera of the presentinvention comprises an image pickup part, an image processing part, acontrol image processing part, and a control part.

[0030] This image pickup part performs “still image pickup for shootinga subject image to generate a still image signal” and “monitor-imagepickup for successively generating monitor-image signals having a framerate higher than that of the still image signal” in time division.

[0031] Moreover, the image processing part applies predetermined stillimage signal processing to the still image signal generated by the imagepickup part and applies predetermined monitor signal processing to themonitor-image signals generated by the image pickup part.

[0032] Furthermore, the control image processing part appliespredetermined control signal processing to the monitor-image signalsgenerated by the image pickup part to extract control data.

[0033] Besides, the control part performs at least one control operationout of exposure control, focus control, and white balance control, basedon the control data output from the control image processing part.

[0034] In particular, the present invention is characterized in that thecontrol image processing part and the image processing part areconfigured to operate independently, and the control image processingpart performs the signal processing on the control image signalssuccessively generated, even when the still image signal is beingsignal-processed.

[0035] In such a configuration, the signal processing of the still imagesignal and the monitor-image signals is performed by the imageprocessing part, which is a single unit. Therefore, it becomes possibleto reduce the circuit scale of the apparatus as compared to the casewhere the still image processing part and the monitor-image processingpart are provided independently. As a result, power consumption caneasily be reduced, resulting in extending the battery life of theelectronic camera.

[0036] Incidentally, in the foregoing configuration, the signalprocessing of the still image signal and that of the monitor-imagesignal cannot be perfectly synchronized. On that account, when the stillimage signal is processed with priority, updating the monitor displaywhile the still image signal is being signal-processed becomesdifficult. Nevertheless, even under these circumstances, the controlimage processing part can extract the control data from themonitor-image signals. Thus, although the monitor display cannot beupdated, the continuity of the control data will not be needlesslyinterrupted and the control data can be obtained as continuously aspossible. Consequently, it becomes possible to mend the adverse effectthat control operations may be delayed because they follow discontinuouschange in control data.

[0037] (5) Another electronic camera of the present invention is theelectronic camera as set forth in the foregoing section (2) or theforegoing section (4), comprising a display part for displaying thestill image signal and the monitor-image signals in a juxtaposedfashion, in a nested fashion, or in a selective fashion.

[0038] When images are displayed in a juxtaposed fashion, it becomespossible to determine the next composition based on the moving imagedisplay by the monitor-image signals and to check the monitor by thestill image signal at the same time.

[0039] Moreover, when images are displayed in a nested fashion, theimages displayed concurrently are more in a subordinate-superiorrelationship than in when they are displayed in a juxtaposed fashion. Itis thus easier to recognize intuitively which image is which.

[0040] Furthermore, when images are displayed selectively, it becomespossible to check the desired image signal alone on the monitor.

[0041] (6) Another electronic camera of the present invention is theelectronic camera as set forth in the foregoing section (5), wherein thedisplay part has a first memory region for storing the still imagesignal for monitor display use and a second memory region for storingthe monitor-image signals, the first and second memory regions beingindependent from each other, and switches the memory region to bedisplayed on a monitor to replace display on the monitor.

[0042] In such a configuration, the two memory regions are independentfrom each other. This makes it possible to replace the display on themonitor quickly by switching the memory region to be displayed on themonitor. This allows such operations as instantaneously replacing thepositions of images to be displayed in a juxtaposed fashion andinstantaneously switching a still image display with a monitor image.

[0043] Incidentally, the foregoing object and other objects of thepresent invention can be seen easily from the following description andthe accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

[0044]FIG. 1 is a diagram showing the configuration of an electroniccamera 11 according to the first embodiment;

[0045]FIG. 2 is a timing chart for explaining the operation of theelectronic camera 11;

[0046]FIG. 3 is a flowchart for explaining the operation of a videooutput circuit 32;

[0047]FIG. 4 is a diagram showing display examples of a display screen33; and

[0048]FIG. 5 is a diagram showing the configuration of an electroniccamera 11 a according to the second embodiment.

BEST MODE FOR CARRYING OUT THE INVENTION

[0049] Hereinafter, embodiments of the present invention will bedescribed with reference to the drawings.

[0050] <<First Embodiment>>

[0051] A first embodiment is one corresponding to the inventions ofclaims 1-5.

[0052] (Configuration of First Embodiment)

[0053]FIG. 1 is a diagram showing the configuration of an electroniccamera 11.

[0054]FIG. 2 is a timing chart for explaining the operation of theelectronic camera 11.

[0055] In FIG. 1, a shooting lens 12 is mounted on the electronic camera11. The image pickup surface of an image pickup device 13 is situated onthe optical axis of this shooting lens 12 via a diaphragm 12 a.Incidentally, for the sake of avoiding smear in reading a still imagesignal after release, a mechanical shutter may be arranged in front ofthe image pickup surface of the image pickup device 13.

[0056] An image signal output from this image pickup device 13 issupplied to a still image processing part 15 and a moving imageprocessing part 25 through an A/D conversion part 14.

[0057] This still image processing part 15 is composed of an imageprocessing part 16 for performing a 2D image process, a thumbnailcreating part 17 for creating thumbnails, a JPEG compression part 18 forperforming JPEG compression, and a size conversion part 18 forconverting image sizes for use in monitor display of still images. Theseprocessing parts 16-19 are connected to a second bus 20 which is usedchiefly for image processing, through FIFO (First-In First-Out memories)21-24, respectively.

[0058] Here, the image processing part 16 performs imperfect pixelcorrection, black level clamp, gain adjustment, white balanceadjustment, tone conversion, color interpolation, color coordinateconversion, filtering, etc. Of these, a series of processes capable ofreal-time processing such as imperfect pixel correction, black levelclamp, and gain adjustment is processed in real time as a first step.Here, white balance adjustment is executed as part of the real-timeprocessing if white balance adjustment values are obtained in advancefrom monitor-image signals or the like. Tone conversion can also beexecuted as part of the real-time processing if it can be processedbefore color interpolation.

[0059] On the other hand, color interpolation and filtering aredifficult to execute as part of the real-time processing since they are2D image processes. Then, these 2D image processes are executed as asecond step while data is exchanged with an image memory 41 to bedescribed later.

[0060] Meanwhile, the moving image processing part 25 is composed of amonitor-image processing part 26 for performing signal processing on amonitor-image signal and a control image processing part 27 forextracting control data from predetermined regions of a monitor image.The output of this monitor-image processing part 26 is connected to thesecond bus 20 through a FIFO 28. Moreover, the output of the controlimage processing part 27 is connected to a first bus 29 which is usedchiefly for system control.

[0061] The image memory 41 is also connected to the second bus 20. Amonitor-display memory region 30 in the image memory 41 is provided withtwo memory regions (viewfinder region 30 a, quickview region 30 b) whichare capable of independent accesses. Incidentally, this image memory 41is also used as a work memory in performing signal processing.

[0062] Moreover, the second bus 20 is connected with a video outputcircuit 32 through a FIFO 31. This video output circuit 32 drives adisplay screen 33 to exercise image display.

[0063] Now, the first bus 29 is connected with a microprocessor 34 forperforming system control, a RAM 35, a ROM 36, and so on. Thismicroprocessor 34 is connected with the still image processing part 15,the monitor-image processing part 26, the control image processing part27, the video output circuit 32, a focus control part 38 for performinga focus control on the shooting lens 12, a diaphragm control part 39 forcontrolling the diaphragm 12 a, a timing generator 40 for controllingthe image pickup device 13 and the A/D conversion part 14, and so on, inorder that control signals for system control are transmitted thereto,respectively.

[0064] Incidentally, these control signals may be transmitted to therespective units through the first bus 29. Incidentally, when amechanical shutter is provided, a control signal of the microprocessor34 is also transmitted to a control unit of the mechanical shutter.

[0065] (Correspondence Between the Foregoing Configuration and thePresent Invention)

[0066] Hereinafter, description will be given of the correspondencebetween the first embodiment and the present invention.

[0067] The image pickup part as set forth in claims corresponds to theimage pickup device 13 and the timing generator 40.

[0068] The still image processing part as set forth in claimscorresponds to the still image processing part 15.

[0069] The control image processing part as set forth in claimscorresponds to the control image processing part 27.

[0070] The control part as set forth in claims corresponds to themicroprocessor 34, the focus control part 38, the diaphragm control part39, the timing generator 40, the monitor-image processing part 26 (awhite balance adjustment function thereof), etc.

[0071] The control image signal as set forth in claims corresponds tothe monitor-image signal.

[0072] The monitor-image processing part as set forth in claimscorresponds to the monitor-image processing part 26.

[0073] The display part as set forth in claims corresponds to themonitor-display memory region 30 for and the video output circuit 32.

[0074] The first memory region as set forth in claims corresponds to thequickview region 30 b.

[0075] The second memory region as set forth in claims corresponds tothe viewfinder region 30 a.

[0076] Next, characteristic operations of the first embodiment will bedescribed individually.

[0077] (Monitor-Image Signals Processing Operation)

[0078] Initially, description will be given of the operation forprocessing monitor-image signals.

[0079] The timing generator 40 drives the image pickup device 13 togenerate monitor-image signals in succession. These monitor-imagesignals are image signals of high frame rate, being generated bypartially reading data that is generated pixel by pixel in the imagepickup device 13. Incidentally, when the image pickup device 13 is aCCD, the monitor-image signals are often signals whose lines arepartially skipped being read.

[0080] The monitor-image signals thus successively generated aredigitized by the A/D conversion part 14 before supplied to both themonitor-image processing part 26 and the control image processing part27.

[0081] The monitor-image processing part 26 performs signal processingfor monitor display (such as color interpolation and tone conversion) onthe monitor-image signals. Concurrently with this signal processing, themonitor-image processing part 26 transfers and records the processedmonitor-image signals onto the viewfinder region 30 a in themonitor-display memory region 30 arranged in the image memory 41 throughthe second bus 20. The video output circuit 32 reads the monitor-imagesignals from this viewfinder region 30 a periodically, and displays themonitor-image signals on the display screen 33 as moving images.

[0082] Meanwhile, the control image processing part 27 extracts aregional image of a focus detection area, a regional image of aphotometric area, and a regional image of a white balance areaindividually from the monitor-image signals. Incidentally, these areascan be changed freely by a control signal from the microprocessor 34.Moreover, unless there is a specific problem, these areas may be unitedto omit redundancy in the processing for extracting the regional images.

[0083] The control image processing part 27 performs operations on theseregional images to extract control data (here, a contrast value, aphotometric value, and a white balance value).

[0084] Concurrently with this extracting operation, the control imageprocessing part 27 successively outputs the extracted control data tothe microprocessor 34 through the first bus 29.

[0085] Here, the microprocessor 34 performs operations based on thecontrol data of the contrast value to drive the focus control part 38,thereby exercising a focus control of contrast hill-climbing method.

[0086] The microprocessor 34 also performs an exposure operation basedon the control data of the photometric value, thereby exercising anexposure control through the diaphragm control part 39 and the timinggenerator 40 (electronic shutter). Incidentally, at the time of thecontrol image pickup (monitor-image pickup), the depth of focus of theshooting lens 12 is better rendered shallower to increase the detectionsensitivity to focus errors (peaks in contrast value). Thus, thediaphragm 12 a is preferably fixed to near release.

[0087] Moreover, the microprocessor 34 transmits the control data of thewhite balance adjustment value to the monitor-image processing part (orstill image processing part) for the sake of a white balance adjustment.

[0088] The focus control and exposure control described above are lockedafter the release is half pressed. During this control lock, theshooting lens 12 is fixed to the focus position and the exposure controlvalue is held by the microprocessor 34 in preparation for still imagepickup by a full press of the release. Incidentally, as shown in FIG. 2,the image pickup operation of the monitor-image signals, the extractionprocessing of the control data, the white balance adjustment, theoperation for a focus control, the operation for an exposure control,and the like continue being performed even after the half press.

[0089] By the sequential processing of the monitor-image signalsdescribed above, the control operation of the electronic camera 11 andthe moving image display of the monitor-image signals continue beingeffected as shown in FIG. 2.

[0090] (Still Image Signal Processing Operation)

[0091] Next, description will be given of the operation for processing astill image signal.

[0092] When the release button of the electronic camera 11 is fullpressed during the operation for processing monitor-image signals asdescribed above, the microprocessor 34 controls the timing generator 40to perform still image pickup (exposure) based on the exposure controlvalue held at the time of the control lock (control of the diaphragm 12a and the electronic shutter), and then reads a still image signal fromthe image pickup device 13. This still image signal is an image signalof high resolution, being read from the image pickup device 13 with nopartial reading.

[0093] The still image signal generated thus is digitized by the A/Dconversion part 14 before supplied to the image processing part 16. Theimage processing part 16 performs, as described above, the real-timeprocessing of the first step and the 2D image process of the second stepon this still image signal.

[0094] Here, if a white balance adjustment is to be made to the stillimage signal by using the white balance adjustment value obtained in theimmediately preceding control image pickup (monitor-image pickup), themicroprocessor 34 sets this adjustment value to the image processingpart 16 before the read of the still image signal so that the whitebalance adjustment is made in the process of the real-time processing.

[0095] The image processing part 16, each time it completes the 2D imageprocess for a minimum unit of processing, supplies the still imagesignal past the 2D image process (YCbCr, RGB, or such an image signal)to the thumbnail creating part 17, the JPEG compression part 18, and thesize conversion part 19 as needed.

[0096] The thumbnail creating part 17 creates a thumbnail image based onthe still image signal supplied thus.

[0097] The JPEG compression part 18 performs JPEG test compression andJPEG full compression based on the still image signal (typically a YCbCrimage signal) supplied thus, compressing the still image signal to atarget code volume.

[0098] Incidentally, the JPEG compression part 18 also performs imagecompression of the thumbnail image during such JPEG compression.

[0099] The compressed image data and thumbnail compressed data processedthus are integrated into JPEG files and stored into a memory card (notshown).

[0100] Meanwhile, the size conversion part 19 performs size conversionfor quickview (monitor check of the result of the image pickup) based onthe still image signal supplied thus. Concurrently with such sizeconversion, the size conversion part 19 transfers and records thesize-converted still image signal onto the quickview region 30 b throughthe second bus 20. The video output circuit 32 reads the still imagesignal from this quickview region 30 b, and makes a quickview display onthe display screen 33.

[0101] Incidentally, when the output signal of the video output circuit32 is a video signal of NTSC format, PAL format, or SECAM format, thesize conversion part 19 is supplied with a YCbCr image signal.

[0102] By the processing of the still image signal described above, thestill image signal is stored and a quickview display is effected asshown in FIG. 2.

[0103] (Concerning Processing of Monitor-Image Signals during SignalProcessing of Still Image Signal)

[0104] Next, description will be given of the processing ofmonitor-image signals during the signal processing of a still imagesignal described above.

[0105] Initially, as shown in FIG. 2, the timing generator 40 restartsthe successive generation of monitor-image signals immediately after thecompletion of read of the still image signal. Here, the still imageprocessing part 15 has started the signal processing on the still imagesignal.

[0106] The control image processing part 27 restarts the operation ofextracting control data from monitor-image signals immediately withouthampering the operation of this still image processing part 15 at all.

[0107] In addition, the monitor-image processing part 26 restarts themonitor signal processing immediately without hampering the operation ofthis still image processing part 15 at all.

[0108] (Concerning Monitor Display Replacing Operation)

[0109]FIG. 3 is a flowchart for explaining the operation of the videooutput circuit 32.

[0110] Hereinafter, the operation for replacing monitor display will bedescribed with reference to the step numbers shown in FIG. 3.

[0111] Step S1: Initially, the video output circuit 32 sets the scanningposition of the display screen 33 to an initial position (such as theupper left of the screen).

[0112] Step S2: The video output circuit 32 determines which screen todisplay mainly (hereinafter, referred to as “main screen”) in accordancewith internal flag information. Here, when the viewfinder is the mainscreen, the video output circuit 32 moves to step S3 in operation. Onthe other hand, when the quickview is the main screen, the video outputcircuit 32 moves to step S5 in operation. Incidentally, themicroprocessor 34 can rewrite the flag information in this video outputcircuit 32 to change the screen to display mainly as needed.

[0113] Step S3: Here, the viewfinder is selected as the main screen.Then, the video output circuit 32 substitutes the top address of theviewfinder region 30 a, the main screen, for a memory pointer P1.

[0114] Step S4: Moreover, the video output circuit 32 substitutes thetop address of the quickview region 30 b for another memory pointer P2.After the completion of such pointer setting, the video output circuit32 moves to step S7 in operation.

[0115] Step S5: Here, the quickview is selected as the main screen.Then, the video output circuit 32 substitutes the top address of thequickview region 30 b, the main screen, for the memory pointer P1.

[0116] Step S6: Moreover, the video output circuit 32 substitutes thetop address of the viewfinder region 30 a for the other memory pointerP2. After the completion of such pointer setting, the video outputcircuit 32 moves to step S7 in operation.

[0117] Step S7: The video output circuit 32 selects the display mode ofthe screen in accordance with internal flag information. Here, when afull screen display is selected as the display mode, the video outputcircuit 32 moves to step S8 in operation. On the other hand, when anested display is selected, the video output circuit 32 moves to step S9in operation. Incidentally, the microprocessor 34 can rewrite the flaginformation in this video output circuit 32 to change the display modeas needed.

[0118] Step S8: The video output circuit 32 reads an image signal fromthe memory pointer P1 and sets the signal value in the scanning positionof the display screen 33. After such setting, the video output circuit32 moves to step S12 in operation.

[0119] Step S9: Since the nested display is selected here, the videooutput circuit 32 determines whether or not the current scanningposition corresponds to the nested screen.

[0120] When the current scanning position does not correspond to thenested screen, the video output circuit 32 moves to step S8 in operationto perform the same operation as with full screen display.

[0121] On the other hand, when the current scanning position correspondsto the nested screen, the video output circuit 32 moves to step S10 inoperation to perform the processing of the nested screen.

[0122] Step S10: To perform the processing of the nested screen here,the video output circuit 32 partially reads an image signal from thememory pointer P2, and sets the signal value in the scanning position ofthe display screen 33.

[0123] Step S11: The video output circuit 32 increments the memorypointer P2 by the partial amount not read, in preparation for the nextpointer reference.

[0124] Step S12: The video output circuit 32 increments the memorypointer P1 and the scanning position in preparation for the next pointerreference.

[0125] Step S13: Here, the video output circuit 32 determines whetherthe scanning is completed or not. If the scanning is not completed, thevideo output circuit 32 returns to step S7 in operation to continuescanning the display screen 33. On the other hand, if the scanning iscompleted, the video output circuit 32 returns to step S1 in operationto repeat the scanning of the display screen 33 from the initialposition.

[0126] (Effects, Etc. of the First Embodiment)

[0127] As described above, in the first embodiment, the generation of amonitor-image signal is restarted immediately after the generation of astill image signal as shown in FIG. 2. In response to this monitor-imagesignal, the control image processing part 27 restarts the operation forextracting control data immediately. Consequently, the control data hashigh continuity, which can effectively preclude the problem that adiscontinuous change in the control data causes a delay in subsequentcontrol operations.

[0128] Besides, in the first embodiment, the monitor-image processingpart 26 performs the processing of monitor-image signals even while astill image signal is processed. It is therefore possible to display themonitor-image signals even during the still image signal processing.

[0129] Moreover, in the first embodiment, the operation of the videooutput circuit 32 described above makes it possible to display fourtypes of screens shown in FIGS. 4(a)-(d) on the display screen 33. Inthis case, the microprocessor 34 can rewrite the flag information in thevideo output circuit 32 to switch these four types of screensinstantaneously.

[0130] In particular, the first embodiment comprises the second bus 20for exchanging still image signals and the first bus 29 for exchangingcontrol data, the buses being independent of each other. This precludesthe still image signals and the control data from conflicting on anidentical bus, and makes it possible to perform the still imageprocessing and the control operations smoothly in parallel.

[0131] Furthermore, in the first embodiment, the image pickup operationof the monitor-image signals, the extraction processing of the controldata, the white balance adjustment to the monitor images, the operationfor a focus control, and the operation for an exposure control arecontinued even after the release is half pressed. The control data andthe operations can thus be maintained at high continuity even after thehalf press. Consequently, it becomes possible to effectively precludesuch adverse effects that the control operations delay restarting afterthe half-pressed state is cleared.

[0132] Now, description will be given of another embodiment.

[0133] <<Second Embodiment>>

[0134] A second embodiment is one corresponding to the inventions ofclaims 1 and 6-8.

[0135]FIG. 5 is a diagram showing the configuration of an electroniccamera 11 a according to the second embodiment.

[0136] The configuration of the second embodiment is characterized inthat the still image processing part 15, the monitor-image processingpart 26, and the FIFO 28 are omitted from the electronic camera 11described above (FIG. 1), and a general-purpose image processing part 15a is arranged instead.

[0137] This general-purpose image processing part 15 a contains an imageprocessing part 16 a. This image processing part 16 a performs stillimage signal processing or signal processing for a monitor imageselectively depending on the type of the image signal (still imagesignal, monitor-image signal) designated by the microprocessor 34.

[0138] Incidentally, since the components and operations are otherwisethe same as in the first embodiment, description thereof will be omittedhere.

[0139] As above, according to the second embodiment, the signalprocessing circuits dedicated to monitor-image signals becomeunnecessary. This makes it possible to reduce the circuit scale of theentire electronic camera. As a result, the power consumption of theelectronic camera can be lowered to extend the battery life of theelectronic camera.

[0140] Moreover, since the control image processing part 27 extractscontrol data even during the signal processing of still image signals,the control data can be obtained as continuously as possible. This canimprove the problem that a discontinuous change in the control datacauses a delay in control operations.

[0141] Furthermore, in the second embodiment, the image processing part16 a for performing image processing for general purpose use and theJPEG compression part 18 and the like for performing signal processingdedicated to still image signals are configured capable of independentoperations. The image processing part 16 a can thus enter the signalprocessing of monitor-image signals quickly after the signal processingof a still image signal shifts to the JPEG compression part 18 and thelike. As a result, it becomes possible to shorten the interruption ofmonitor display.

[0142] (Supplemental Remarks on Embodiments)

[0143] Incidentally, in the embodiments described above, regional imagesare cut out of the monitor-image signals, and control data (such as acontrast value, a photometric value, and a white balance value) iscalculated from these regional images. However, the control data is notlimited thereto. For example, the control image processing part 27 maycut regional images out of the monitor-image signals and transmit theseregional images to the microprocessor 34 as the control data. In thiscase, the microprocessor 34 performs operations for a contrast value, aphotometric value, a white balance value, etc. based on the regionalimages.

[0144] Moreover, in the foregoing embodiments, the control data is notextracted from the still image signal. However, this is not restrictive.For example, the control image processing part 27 may extract controldata from the still image signal (see dotted portions shown in FIG. 2).In this case, the continuity of the control data can be enhancedfurther, allowing an additional improvement to the adverse effect thatsubsequent monitor display and still image pickup might get delayed dueto a discontinuous change in the control data.

[0145] Incidentally, the foregoing embodiments have dealt with the caseswhere the video output circuit 32 makes a full screen display and anested display. However, this is not restrictive. For example, the videooutput circuit 32 may arrange two screens on the display screen 33 forjuxtaposed display.

[0146] Moreover, in the foregoing embodiments, the video output circuit32 switches the memory pointers P1 and P2 in accordance with thescanning position of the screen. However, this is not restrictive. Forexample, image signals may be read from the two memory regions 30 a and30 b in parallel (as concerns a nested screen, partial read shall beperformed) so that the video output circuit 32 selects which imagesignal to display in accordance with the scanning position.

[0147] By the way, in the present invention, the control data has highcontinuity even during the signal processing of the still image signal.This improves the continuity of the focus control and the like.Consequently, the next release operation can be accepted easily evenduring the signal processing of the still image signal. In such a case,it is preferable to perform either of the following operations:

[0148] 1) The still image processing part 15 continues the signalprocessing of the still image signal (2D image process in particular)and captures the released still image signal (at least temporarilyrecords the same on the image memory) concurrently. Incidentally, thecapture is preferably accompanied with the real-time processing.

[0149] 2) The still image processing part 15 suspends the signalprocessing of the still image signal, captures the released still imagesignal (at least temporarily records the same on the image memory) as aninterrupt, and restarts the suspended signal processing after thecompletion of the capture. Incidentally, the capture is preferablyaccompanied with the real-time processing.

[0150] These operations can reduce the possibility of missing the rightmoment for a valuable shot.

[0151] The invention may be embodied in other specific forms withoutdeparting from the spirit and essential characteristics thereof. Theforegoing embodiments are therefore to be considered in all aspects asillustrative and not restrictive. The scope of the invention isindicated by the appended claims rather than by the foregoingdescription. All changes which come within the meaning and range ofequivalency of the claims are therefore intended to be embraced therein.

1. An electronic camera comprising: an image pickup part for performing“still image pickup for shooting a subject image to generate a stillimage signal”, and “control image pickup for successively generatingcontrol image signals having a frame rate higher than that of said stillimage signal” in time division; a still image processing part foraccepting said still image signal generated by said image pickup partand applying predetermined still image signal processing thereto; acontrol image processing part for accepting said control image signalsgenerated by said image pickup part and applying predetermined controlsignal processing thereto to extract control data; and a control partfor accepting said control data output from said control imageprocessing part and performing at least one control operation out ofexposure control, focus control, and white balance control, based onsaid control data, wherein said control image processing part and saidstill image processing part are configured to operate independently, andsaid control image processing part performs the signal processing onsaid control image signals successively generated, even when said stillimage signal is being signal-processed.
 2. An electronic cameracomprising: an image pickup part for performing “still image pickup forshooting a subject image to generate a still image signal” and“monitor-image pickup for successively generating monitor-image signalshaving a frame rate higher than that of said still image signal” in timedivision; a still image processing part for accepting said still imagesignal generated by said image pickup part and applying predeterminedstill image signal processing thereto; and a monitor-image processingpart for accepting said monitor-image signals generated by said imagepickup part and applying predetermined monitor signal processingthereto, wherein said monitor-image processing part and said still imageprocessing part are configured to operate independently, and saidmonitor-image processing part performs the signal processing on saidmonitor-image signals successively generated, even when said still imagesignal is being signal-processed.
 3. The electronic camera according toclaim 2, comprising a display part for displaying said still imagesignal and said monitor-image signals in one of a juxtaposed fashion, anested fashion, and a selective fashion.
 4. The electronic cameraaccording to claim 3, wherein said display part has a first memoryregion for storing said still image signal for monitor display use and asecond memory region for storing said monitor-image signals, said firstand second memory regions being independent from each other, andswitches the memory region to be displayed on a monitor to replacedisplay on the monitor.
 5. The electronic camera according to claim 2,comprising a control image processing part for accepting saidmonitor-image signals generated by said image pickup part and applyingpredetermined control signal processing thereto to extract control data;and a control part for accepting said control data output from saidcontrol image processing part and performing at least one controloperation out of exposure control, focus control, and white balancecontrol, based on said control data, wherein said control imageprocessing part and said still image processing part are configured tooperate independently, and said control image processing part performsthe signal processing on said control image signals successivelygenerated, even when said still image signal is being signal-processed.6. An electronic camera comprising: an image pickup part for performing“still image pickup for shooting a subject image to generate a stillimage signal” and “monitor-image pickup for successively generatingmonitor-image signals having a frame rate higher than that of said stillimage signal” in time division; an image processing part for applyingpredetermined still image signal processing to said still image signalgenerated by said image pickup part and for applying predeterminedmonitor signal processing to said monitor-image signals generated bysaid image pickup part; a control image processing part for acceptingsaid monitor-image signals generated by said image pickup part andapplying predetermined control signal processing thereto to extractcontrol data; and a control part for accepting said control data outputfrom said control image processing part and performing at least onecontrol operation out of exposure control, focus control, and whitebalance control, based on said control data, wherein said control imageprocessing part and said image processing part are configured to operateindependently, and said control image processing part performs thesignal processing on said control image signals successively generated,even when said still image signal is being signal-processed.
 7. Theelectronic camera according to claim 6, comprising a display part fordisplaying said still image signal and said monitor-image signals in oneof a juxtaposed fashion, a nested fashion, and a selective fashion. 8.The electronic camera according to claim 7, wherein said display parthas a first memory region for storing said still image signal formonitor display use and a second memory region for storing saidmonitor-image signals, said first and second memory regions beingindependent from each other, and switches the memory region to bedisplayed on a monitor to replace display on the monitor.